LinuxWhat is the WAD file format?
WAD files are used by the Doom series of computer games and many other titles built on this landmark FPS engine, developed in the early 1990s. The name stands for "Where's All the Data".
What are the contents of WAD files?
The WAD format was designed with storing game data in mind. A single .wad file bundles all game content as a flat list of named data chunks called lumps. WAD files can contain:
- textures and sprites,
- maps and level geometry,
- graphics and interface elements,
- sound effects and music,
- inventory items and weapons.
WAD files are used for storing both original game data and mods and extensions to the base game.
What are IWAD and PWAD files?
Doom was a great hit on the FPS (first-person shooter) games market. Its popularity soon resulted in fans creating custom maps, weapons, and items - with more advanced modifications to the physics engine and textures following quickly. In order to manage the resulting variety, the WAD standard was divided into two separate types:
- IWAD - stores the original, complete game data (
DOOM.WAD,DOOM2.WAD, etc.), - PWAD - stores mods and add-ons that patch or extend the base game.
This distinction is encoded in the first four bytes of every .wad file (IWAD or PWAD as an ASCII tag). Further iterations of the original Doom engine were used as the basis for games that became great hits - Heretic, Hexen, and Quake among them. The WAD format evolved into newer variants such as WAD2 and WAD3; in Half-Life, WAD3 files are used only for saving game textures.
Can I open a WAD file?
Doom gained huge popularity not only thanks to its innovative gameplay, but also from the proliferation of fan-made modifications, which were easy to create by editing .wad files. Dedicated WAD editors such as SLADE 3 and Ultimate Doom Builder are freely available. Although Doom debuted over 30 years ago, fans still create new maps and total conversions by editing WAD files. Modern source ports such as GZDoom load both classic .wad files and the newer PK3 (ZIP-based) format used for complex modern mods.
Security & safety
RISK: LOWA Doom WAD file is a plain game archive with no executable code - the game engine runs the code, not the WAD. WAD files are safe to open in Slade or a source port. Two caveats: (1) some third-party "WAD downloader" sites bundle adware in their installers - get mods from Doomworld's idgames archive or recognized community sites; (2) do not confuse Doom WADs with Wii WADs (Nintendo Wii packages), which can affect a Wii's system firmware and require different handling.
Format details
in a nutshell- Wii WAD - Nintendo Wii channel/game packages use a completely unrelated binary format also called WAD; Wii WADs install content to the Wii System Menu via different homebrew tools.
- Tropico save/data file - The Tropico city-building game series has used a .wad extension for its own proprietary data archives, unrelated to Doom.
Programs that open WAD files
Windows5 apps
GZDoom
Open-source Drag the IWAD and any PWAD onto GZDoom.exe, or run 'gzdoom -iwad DOOM2.WAD -file mod.wad'. The most feature-rich and widely used Doom source port.
Crispy Doom
Open-source Run 'crispy-doom -iwad DOOM.WAD' for a near-vanilla experience. Good for classic maps without modern GZDoom extensions.
Slade 3
Open-source Open any WAD in Slade to browse, extract, and edit all lumps (maps, textures, sounds, sprites). The standard free WAD editor/viewer.
Doom Builder (Ultimate Doom Builder)
Open-source Open or create map lumps from a WAD for visual map editing. The standard free Doom map editor.
Doom II (via Steam/GOG)
Paid Purchase the classic game to get an official DOOM2.WAD IWAD, which then works with any source port or the included (KEX) engine. 
macOS2 apps
Technical details
deep spec| Magic bytes | "IWAD" (0x49 57 41 44) or "PWAD" (0x50 57 41 44) at byte offset 0 |
| Encoding | Binary (flat lump archive) |
| Byte order | Little-endian (x86) |
| Compression | None (in the container itself) |
| Typical file size | 1 MB - 600 MB (DOOM2.WAD ~14 MB; large megaWADs up to 600 MB+) |
| MIME type | application/x-doom-wad |
| Header structure | 12 bytes - 4-byte type tag + 32-bit lump count + 32-bit directory offset |
| Directory entry | 16 bytes fixed - int32 data offset, int32 size, 8-character lump name |
| Audio lump format | Doom DMX (11-22 kHz mono 8-bit PCM); MUS or MIDI lumps for music |
| Color depth | 8-bit (256-color Doom palette) for in-game art; source ports support true color |
| Max lump count | Up to ~4.29 billion (32-bit unsigned count field) |
| IWAD vs. PWAD | IWAD = complete base game data; PWAD = mod/patch that overrides or adds lumps |
| Released | December 1993 (Doom v1.0); format thoroughly documented by the community |
| Latest version | Format essentially unchanged since Doom II (1994); source-port extensions (ZDoom UDMF, etc.) use compatible supersets |
| Specification | doomwiki.org |
WAD conversions
Community Q&A
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